Certain types of centrifugal separators have a rotor that is situated on an uppermost portion on a vertical rotor shaft and comprises a hub connected to the rotor shaft. Typically, the hub has a connection which is configured for the rotor shaft and which is conical and extends axially inwards in the rotor's inner space, and a portion of the rotor shaft which is inserted in the rotor's hub has a corresponding conical shape and likewise extends inwards in the rotor. The conical shape results in self-locking of the hub and the rotor shaft during rotation, thereby achieving during operation a transfer of torque between the rotor shaft and the rotor. The conical shape also results in self-centering of the rotor on the rotor shaft. Within the rotor, a nut is provided on the end of the rotor shaft to lock the rotor axially to the rotor shaft. The nut thus provides protection against (axial) forces which may act upon the rotor during operation. Removing the rotor from the rotor shaft involves first dismantling the rotor's constituent parts in order thereby to open up its interior so that the nut can be removed. Such dismantling is relatively time-consuming.
Other types of centrifugal separators have a connection between the rotor shaft and the hub similar to that described above. Consequently, this hub likewise has a conical connection which extends axially inwards in the rotor's inner space, and the portion of the rotor shaft which is inserted in the hub has a corresponding conical shape and likewise extends inwards in the rotor. These centrifugal separators comprise a duct extending axially within the rotor shaft and serving as an inlet for the liquid fluid mixture which is to be separated in the rotor. The duct leads into a so-called distributor through which the liquid mixture is supplied to the separating chamber. During operation, the configuration of the inlet with the duct and the distributor causes the liquid mixture to follow a transfer path in which there are two relatively large changes of direction of flow (about 155° each). The first change of direction is at the transition between the duct and the distributor and the second change of direction is at the transition from the distributor upwards to the separating chamber. Such large changes of direction cause the liquid mixture fed to the separating chamber to be subject to undesirable flow resistance and pressure drop.